1. Field of the Invention
This invention relates generally to an automatic transmission brake hub that reduces hydraulic drag due to open-brake rotation and eliminates transmission case splines.
2. Description of the Prior Art
In a hydraulically-actuated automatic transmission for a motor vehicle, transmission brakes produce high drag losses, which adversely affect fuel economy.
When the brake's separator plates are splined directly to the transmission case, automatic transmission fluid in the case is difficult to evacuate, which leads to high drag. When the brake's separator plates are splined directly to the transmission case, installation of the separator plates and friction plates must be completed as a final assembly, instead of as a subassembly, which is preferred.
Forming spine teeth in the transmission case that engage spline teeth on the brake's separator plates can be costly to machine and produces excessive, unwanted scrap.